FACULTY OF TECHNOLOGY

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Subject: search.filters.subject.Heat exchanger

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    Crossflow flow and heat transfer characteristics across a cam-shaped tube bank: a numerical study
    (2022) Petinrin, M. O.; Sikirullahi, B. A.; Olugasa, T. T.; Oyewola, O. M.
    Tubes are commonly employed in heat exchangers for their ease of production and capacity to sustain high pressure. In this study, the heat and flow transfer behaviour of cam-shaped tube bank in staggered configuration at varying angles of attack 0° to 180° was numerically investigated. The study was carried out by solving the continuity, momentum, energy and realizable k-ε transport equations using the finite volume-based ANSYS Fluent solver. This was performed to acquire the friction factor and heat transfer characteristics in the air inlet velocity range of 9 to 15 m/s. The results showed that the cam-shaped tube bank at varying angles of attack provided enhanced heat transfer characteristics relative to the circular tube bank. Also, camshaped tube banks at angles of attack of 90° and 120° exhibited the maximum heat transfer with 33.9 and 32.1% increase in Nusselt number over the circular tubes. Their friction factor was higher by 183 and 140.7%, respectively. The cam-shaped tube banks generally exhibited higher performance than the circular tube bank. Tube banks at angles of attack of 150° and 180° demonstrated higher thermal-hydraulic performance by 167.6 and 284.3% than the circular tubes, respectively. However, the tube banks at angles 90° and 120° exhibited lesser performance by value of 52.6 and 45.1%.
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    Control modelling of coupled shell and tube heat exchangers using combined neural network and fuzzy logic
    (2022) Petinrin, M. O.; Oke, O. S.; Adebayo, A. S.; Towoju, O. A.; Ismail, O. S.
    Control of the temperature of the outlet fluid in heat exchanger network is very important to maintain safety of equipment and meet the optimal process requirement. Conventional PID controllers have the limitations of meeting up with wide range of precision temperature control requirements, and then the predictive controllers have recently emerged as promising alternatives for advanced process control in heat exchanger systems and other industrial applications. This paper focuses on the control of output temperature of coupled shell and tube heat exchanger by combining fuzzy logic and Neural Network control system. To achieve effective control, transfer functions from the energy balance equations of the heat exchanger unit and other components were obtained. Simulation of the control process was carried out using Simulink interface of MATLAB. The time response analysis in comparison with variants of conventional PID controllers shows that combination of Neural Network and fuzzy logic controllers can efficiently improve the performance of the shell and tube heat exchanger system while in with 0.505% overshoot and less settling time of 12.74 s, and in parallel with the same overshoot of 0.505% and settling time of 11.37 s. The demonstration of the lower error indices of the neuro-fuzzy controlled system also indicated its better performance.
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    Finite element stabilization methods and solvers for heat exchanger applications: a review
    (2016) Petinrin, M. O.; Dare, A. A.; Asaolu, G. O.
    This review focuses on the applications of finite element method (FEM) for heat exchanger analyses. Solutions to convection-dominated heat transfer problems using the Galerkin FEM approximation are always characterised with errors caused by numerical instabilities. Efforts to enhance the stability and exactness of results had led to development of a number of stabilization techniques. Also, there have been algorithms formulated to effectively solve the sparse symmetric and non-symmetric matrix systems resulting from FEM discretised equations of thermal flow problems. The development of stabilization techniques and solvers has made the FEM approach a more formidable computational fluid dynamics (CFD) tool. However, there have been limited uses of finite element CFD codes to heat exchanger applications.